Dynamo-electric machine.



R. B. WILLIAMSON. DYNAMO ELECTRIC MACHINE. APPLICATION FILED NOV. 20, 1909.

Patented June 18, 1912.

'cnrrnn STATES PATENT OFFICE.

nosnn'r :s. wimirmson, or mnwnonnn, wrsconsm, ASSIGNOR TO ALLIS- cnamrnns company, A CORPORATION on NEW JERSEY.

DYNAMO-ELECTBIC MACHINE.

PatentedJ 1118-18 1912.

Application filed November 20, 1909. Serial N0.'5 29,008.

To cZZ whom it may concern:

it known that 1, ROBERT B. VVILLIAM: nos, a citizen of the United States, residing at liiilwaukee, in the county of Milwaukee and State. of \Visconsin, have invented cermin new and useful Improvements in r mine-Electric Machines, of; which the following is a full, clear, and exact specification Th' invention relates to dynamo-electric Iir-H lnes and particularly to self-starting ironous motors.

it is a well known fact that a synchros motor may be rendered self-starting by on the rotary member of the w'ondary circuit in which ourinduced, that the motor may i ar'ied and brought up to synchronous speed an induction motor. 'The'secondcircuit usually consists of bars extendthrough the poles of the field magnets d short circuiting rings connected to the s of the bars and located on opposite of the field magnets, the bars and rings formed of copper or othersuitable c nducting iioaterial. It has also been roo d to utilize as part of the secon ary the form of coilars which surround the other ends of the poles and are connected together he short circuiting rings. These dealthough successful for starting pure not very efiicient because of the inc'e of the. secondary circuit and Us the it v currents which are induced there- Furthermore the secondary circuit, ex: oi in those machines wherein parts of the clr is in operation, as above stated, is of no up to synchronous speed.

The object of the present invention is to improve the efilciency and utility of starta, an

I c-onnect cent field r be n.

n our *1 dampers or anti-hunting devices in L'- serve dampers after the machine utility after the machine has been broughting devices of the above character for syn sections, each 'having portions which are connected to the conductors on adjacent field magnets and intermediate portions of a shape such that they not only render the resistance between the conductors on ad- 5 jacent field magnets considerably reater. .than "the corresponding portions 0 ordi nary short circuiting rings, but also provide large heat radiating surfaces and serve as fan blades to cool the field magnets and stator when the machine is in operation;

. My invention may be further briefly summarized as consisting in certain novel details of construction and combinations and arrangements ofparts which will, be de I scribed in the specification and set forth i the appended claims.

For an understanding of my invention reference is had to the accompanying sheet of drawings whereini Figure l is a perspective view of a portion of a rotary field member of a synchronous motor equipped with the preferred form of my invention. Fig. 2 is a sectional view taken through a portion of the stator 30 of the motor and through a portion of the)" I rotor, part of a field magnet being showni in elevation and part in section, the section being taken substantially through -the cen-' ter of the field magnet. Fig. a view similar to Fig. 2 showing a slight modifiration of my invent-ion. i Referring now to1the figures of the drawing, 10 represents a portion'of the stator and 11 a portion of the rotor or rotary field member of a synchronous motor, the stator, which may be of the usual construction, comprising a-frame 12, a laminated core 13 and a winding 14 supported at the inner periphery of the stator core. The rotor 11 includes a spider having a rim 15 to which are secured a number of field magnets 16 each. having a pole 17 built up of laminae which are clamped between end lites 18, and each pole being surrounded y a coil 19 which, in this case, is formed of edgewise wound strap copper. The parts so far described may be of the usual constructions. a

Before specifically describing the features 9 which constitute the present invention, itmay be said that Ihave here shown a secondary circuit for rendering the motor selfstarting composed partly of dampers for preventing huntingor fluctuations in the no,

. speed of the motor'aboveor below synchronism, the dampers serving as conductors in which currents are induced when the motor is being brought up to speed as well as forming seats of induced currents to prevent hunting in a well known manner. It is immaterial, however, as far as certain features of my invention are concerned whether dampers or other conductors extending transversely of the field magnets are utilized in the secondary circuit,

Mounted on the outer ends of the field poles are collars which in Figs. 1 and'fl are designated by the reference character 20 each collar, as will be seen, bein provided with a portion 21 which surrounds the pole and extends between the outer end of-thecoil 19 and thepole tips 22" on two sides-of the field magnet and the coil-retaining flanges 23 which project from the end plates on the other two sides of the'field magnet.

The collar isalso provided on iopposite sides of the field magnet, with; a pull offlanges 24 which extend radially outward from the collar outside'of the flanges! 23 of the end plates, and extending transversely through theJaminae and end platesfof the pole and see red at their outer ends to these outwardly extendingfianges 24 are a number of bars 25 which, together with the collars- /20,'constitute the dampers ,or anti-hunting devices o-f'the machine. The theory of. operation of. these dam rs is so well known that further jdescriptronof the same neednot be given. 5

In the construction shown in Figs. 1 and 2 the collars 20'have portions 26 which extend outwardly or laterally beyond the coils as continuations of the portions 21 which are clamped between the coils and the coilretaining projections at the outer end of the pole, and at the extremities of these out wardly extending portions 26 are two flanges 27 which extend radially inward for a short distance along the coil on opposite sides of the field magnet. 3

Instead of connecting together the collars by ordinary short circuiting rings I employ short circuiting sertions 28 which are-pref crably in the form of castings of suitable cmlduciirg material and which connect together the coll trs on adjacent field magnets on both sides of the rotary member. Zach of these sections consists neferably of a flat U-shaped portion 29 and of a pair of a ms 3W \vh'ch are integral respectively with ing' collars on two ad acent field magnets.

the two sides of the U-shaped portion 29 and extend in opposite directions therefrom, the arms 30 being secured by bolts 31 to the inwardlyextending flanges 27 of the damp- The arms 30 not only engage the outer faces of the flanges 27, but, as shown clearly in Fig. 2, have portions 32 which extend under these flanges so as to assist in holding the 'sll modifications sections in place; The flat. U-shaped por tions' 29 are preferably arranged radially and transversely with respect to the plane of rotation of the field magnet. The dampers together with the short circuiting sections form a closed secondary by means of which the motor can be started as an induction motor and brought up to synchronous speed in a well known manner, currents bemg induced in the sides of the collars which extend transversely of the field magnets and in the damping bars which extend transversely through the poles. The portions 29 ofthe' short circuiting sections provide co'n-. siderable resistance between the collars ordampers on adjacent field magnets; they absorb considerable of the heatgeneratd by the provide large heat radiating surfaces; and when the machine is in operation act as 'fan blades to cool the stator 10 and the stator winding 14. In the construction statorlO and rotor 11 struction as previously pers and the manner of securing the .short shown in Fig. 3 the are of thesame conc1rcuitingconductors thereto only being slightly varied. In this case each field magnet is provided with a damping collar 33 having a portion 34 which surrounds the pole and is located as in the first instance,

between the coil and the coil-retaining portion of the pole. At opposite sides of the field magnet this collar is provided with flanges 35 which are quite similar to the flanges 24. of the construction first described and extend radially outward from the portion 34 along the flanges of the 'end plates between which the laminae of the pole are clamped. Extending through the laminae and end plates of the pole, as in the first instance, the outer ends of which are secured to these flanges Instead of providing separate flanges to which the short circuiting sections may be connected, the latter which are designated by the reference character 37 and are of substantially the same shape and conparticularly described, the damare damping; bars or conductors 36 struction as the sections 28 previously de 1 scribed, are secured by bolts 38 to the outby Letters Patent is 1. In a synchronous dynamo-electric machine, of field magnetsconsisting of field poles and coils, a secondary circu t carried b tary member for rendering the mac inc selfstarting comprising conductors extending the ro- '115 wardly projecting flanges 85 to which the a rotary member having a plurality 

